Siemens has been selected by Powergrid to refurbish the 500 MW Vindhyachal high voltage direct current (HVDC) back-to-back system in Madhya Pradesh. The system was commissioned in 1989 to interconnect the asynchronous 400 kV alternating current networks of the northern and western regions. By installing the latest HVDC components, Siemens will extend the useful life of the link. This will be Siemens’ first HVDC modernisation project in India. The upgrade is expected to be completed in 2021. The project’s scope of work includes the installation of new thyristor valves, converter cooling systems, HVDC control and protection systems, direct current measuring devices and surge arresters.